PEOPLE – PRINT – HISTORY

Menu

The Great Boston Molasses Flood, 1919.

On 15 January 1919, a massive tank containing 2.2m gallons of molasses burst in Boston, causing the death of 21 people.

Photograph: Bettmann/Bettmann Archive

An obscure accident led to the first class action lawsuit against a major company, paving the way for modern regulation.

It may sound like the fantastical plot of a children’ story but Boston’s Great Molasses Flood was one of the most destructive and sombre events in the city’s history.

On 15 January 1919, a muffled roar heard by residents was the only indication that an industrial-sized tank of syrup had burst open, unleashing a tsunami of sugary liquid through the North End district near the city’s docks.

As the 15-foot (5-metre) wave swept through at around 35mph (56km/h), buildings were wrecked, wagons toppled, 21 people were left dead and about 150 were injured.

Now scientists have revisited the incident, providing new insights into why the physical properties of molasses proved so deadly.

Presenting the findings last weekend at the American Association for the Advancement of Science annual meeting in Boston, they said a key factor was that the viscosity of molasses increases dramatically as it cools.

This meant that the roughly 2.3m US gallons of molasses (8.7m litres) became more difficult to escape from as the evening drew in.